Tire Pressure & Mileage

[Rick]

Had a slow leak in a rear tire on my Thunderbird. I noticed my instant mileage went down proportionally with the amount of under inflation in the tire. When the tires are inflated correctly I get around 30 mpg but 10 pounds under inflation on one tire drops me to around 22 mpg.


I've known a low tire burns more gas but I didn't realize how much until now.

[raymeketa]

My Toyota Avalon Limited has built in sensors that turn on a warning light when pressure in any tire drops by 2 or 3 pounds. I get an average of 33 MPG highway keeping the pressure at maximum recommendation. I've never tried it at any less pressure.

[John Kepler]

My Toyota Avalon Limited has built in sensors that turn on a warning light when pressure in any tire drops by 2 or 3 pounds. I get an average of 33 MPG highway keeping the pressure at maximum recommendation. I've never tried it at any less pressure.

Yeah......those "wonderful" little tire pressure sensors (Toyota ain't the only one that has'um!) that make your tires VERY difficult to work on, fail frequently, and cost somewhere between $70 and $120 a pop to replace! All to replace a $2 tire pressure gauge and 30 seconds of time! Ain't "progress" wonderful!

[High Plaines Doug r]

I run three cars with the tire pressure at 40-44 psi (the rated max on the sidewall) One is a 1999 Cadillac Seville, next is a 2001 Isuzu Trooper and the latest is a 2011 Toyota Corolla. Tire wear is really good and even from inside to outside but I rotate religiously. Ride can be a little harsh. I record my mileage and gas-ups each fill. Mileage has improved maybe .2-.5 mpg over the recommended pressure. I have deflated to 28-32 psi during the winter months for better traction. My impression is that max tire pressure improves mileage but not much.
Ask for a tire gauge at the place you buy tires. If they don't give you one for free; you are doing it wrong.

[Mike Josephic]

Don't inflate your tires to the MAX INFLATION level imprinted on the tire.
This is not a safe practice. This is the maximum safe inflation level for that
particular tire -- but not necessairly the one correct for YOUR CAR. Incorrect
inflation effects tire life, handling, increased blow-out or tire damage possibilities,
etc.

Read the owners manual or look at the sticker on you door or glove box
that gives the factory recommended inflation for YOUR CAR. They give a range,
usually a "normal load" and a "full load". Pick one that best suits your needs.

Also, please take into account now that we're heading into colder winter temperatures
that you lose air pressure as the temps go down. In other words, you will need to add
a few pounds of air pressure to comphensate for this. Check at least monthly.

Mike

[phil441]

Ditto on the "Don't inflate your tires to the MAX INFLATION level".
Our local Quick Lube place had a habit of doing that and I finally started telling them to leave the tires alone. The last time the wife went there for a lube she overheard a phone conversation between the manager and an irate customer. Seems the customer had a blow-out as he left the store and entered the freeway. The tire shop where he sent the car found his tires grossly over-inflated.
That "MAX" number on the tire means the MAX inflation before the tire heats up from driving or loading.

[Guamsst]

Inflating to the max rating is not " gross OVERinflation " Yes, many cars have a different rating from what's on the tire. No, it is not going to cause a blowout as soon as you start driving. Look at the Ford exploders that had so many blowouts and rollovers, that was due to what? under inflation! Leave your tires anywhere from the manufacturers suggestion (excluding Ford Exploders) and the max rating on the tire. Never ever trust a tire shop. They do not hire mechanical engineers to check tire pressures. I have no idea how many times I have picked up my truck to find it had 4 sloppy flat tires on it and goober was so proud because he caught my dangerously "over inflated tires" Yep, he put them all at 32PSI right where ALL cars should have their pressure set. I bumped them all back up to 42 on a 44max and no longer feel like I am driving on a marshmallow road. Same crap on my moms van. Some other goober set her tires to 32. They actually looked almost flat. If you hit a bumb the thing wallowed all over the road like the S.S. Minnow. Bumped up to 40 and it rides like a van instead of a shrimp boat.

Round tires roll easier, more pressure keeps them more round. That flat spot on the bottom kills mileage.

[JB White]

I do the same with my Lincoln. Adjust the pressures between the door label and the sidewall max. I get much better handling and the mpg average is a few gallons higher.

The Grand Am has the pressure sensors and I'm ready to discombooberate that entire system along with the 'change oil' idiot lights.

[John Kepler]

"Discombooberate" it? Lotsa luck! Obamy and his Gang made it a "critical system", and your ECM computer will go ape-$hit if you do much of anything to it. And here you thought you actually owned your car!

[amber]

Yeah......those "wonderful" little tire pressure sensors (Toyota ain't the only one that has'um!) that make your tires VERY difficult to work on, fail frequently, and cost somewhere between $70 and $120 a pop to replace! All to replace a $2 tire pressure gauge and 30 seconds of time! Ain't "progress" wonderful!

Came out of the VA Hospital last month, got in my Toyota Highlander, drove a few feet until I realized that my right front tire was completely flat. The "low pressure" tire sensor did not pick this up.

You are absolutely right, So much for progress!!